lapsley



. VV'ff-ing arms,12, projecting' from;

--'which'perforation is formed with A 15, ofa smaller diameterfat' its, e

*WILLIAM ABRM vvn'renfnl oF'JvE srnINGGEoRGIA, AssieNoRfoF- l ONE-HALF rro J. B.\LAPsLEY,- oF sans PLACE AND' q. w.' inlrsLEY,

or cALnRA, ALABAMA.

SPECIFICATION forming per; pf Letters I' 5 Floyd and State' of Georgia, have invented certain new and usefnl Improvements in Surveyors Levels; and I do hereby declare that the f following is a full, clear, and exact'description of v the invention, which ywill enable others make and use the same, reference lbeing had f tothe accompanying drawings,which forma part of this specification, and in which@- l portion of my improved survejorslevel, -Fig. 2is a longitudinal vertical sectional view of the same. Figs. 3 and 4 are views of the cross'- bars at the ends of the level-bar, and Fig,5

is a. view'of the inner side of the sight-bar.' Similar numerals of reference indicate cor-V responding parts in all the figures.

Y My invention has relation to levels for sur- "veying; and it consists in theimproved'construction and combination of Y parts of the claimed. l .i In the accompanying drawings, thenumer'al p 1 'indicates the level-bar, which is vprovided .with a spirit-level, 2, at its center and with a groove or recess, 3, at the'iniddle of its-under' sdeyhaving two screw-,threaded jperf 4. Y u" `.5. C ,16,- k; M v

"filponits upper side, which,ribfvits ihto'the perforations 8 in the en ds of this'crossheadl into the threaded perforations Iinthe reeesslof the bar,'securing the cross-head to the under` The cross-headvhas a centrali.' 'j io/downwardlyprojectin'g'shank, 9, whichY is ff-:formed with an annular `flange or ri`m, 1'0,

facing downward and fitting against a similari V iside of the bar.

rim, 11, supported from twocurvedconvergfA s ew-bolt,r16, passinfrfrombelo lips, 22, atdiametrically opposite portions of skilled in the art t'o which'it appertains to gtk-.The lowerlframe is 'formedwith acentral' Figure 1 is a perspective view 'oftheupper .'apertu1'e, 25, 'registering' with the aperture'in.

"screws 26 pass throughy thetwo frames from upper endof a shank, `28, passing through a ,platesfoiming a ballandl'socket joint.; The

same,as hereinafter niore'lfully described and u u "'i' Yperforated lpslbearagalnstthe upper s1de4of75 legs 31 throne' A cross-head, 5, is provided-kmh afrit, 6,-v rjfrhe ends'ff the level-bar recess or groove, and screws -7` pass through groov'esin the under sides of1 en'dsofn the l fame, 1,3, and.

.nel

Patent Nql s'efos', dated April 5,1887. applicati n'meq october ,iesalscsni'nt. 21am. immonet) gthe."smaller of tlie l perforation and?. v'5o through an axial'perforation, 17, in the shank, the bolt having'a nut5`18, at its upper end.

` VThe frame 13 is circular and' formed with a. central perforation, 19,A beveledfrom the uni' l der side, and the-frame'iits within an up-` 55- wardly-projecting circular an'ge, -'20,f upon the upper face of, a frame, 21 having four the frame at' right angles-to each other, the said lips having' screw-threaded perforatlons 6o' A v 23,"through which pass screws 24.

the circular frame, beveled from above, and 6 ,A p'

the under side,"uni'ting'tl1e two frames.;r L l l Aspherical knob, 27, isformed upon'the v plate, 29, and this knob fits in 'the beveled 'apertures' of the Iframes, the frames fitting 'o upon-the knob andvrocking in all directions uponl the saine, th'e"knoband' theapertured lower ends ofthe screwspassingthrough the the'plate, andthe' underside of thisjp'late is provided'withradiating ribs or wings 30, t0 whichi the upper slotted'iend'sv of ,the tripod' Y are pivoted upon' bolts 3 2, passing h the ends of the legs nd throuvh the are forme with.

secured' inf flat 'faces 33,` 'an"d" plates 34'are` bar and have" cross-heads '3o I y Y yond the ends-0f 'the bar, set-screws 33py ing up'throug'h the "ndsfof the'erossfheads. i'-

"credvtothe-f'iat faces at i fberews' p jends of these arms, swinging parallel to theV upper edge of the cross-bar, and the arin 43 is provided with a downwardly-projecting liandle, 45, by means of which the arm and con! 5 sequently the parallel bar may be tilted.

When the level is to be used,the tripod is position, the lour screws in the frame rocking ifm upon the spherical knob, enabling the frames to be adjusted in a horizontal plane, bringing the shank in a vertical line, the position bei'ng tested by turning the level-bar upon the pivotal shank, the level-bar being perfectly i 5 horizontal, when the bubble in the spirit-level will remain stationary at all positions of the level-bai. mi level-bar niay now be diwrcted toward tliemgtpemianandits/Erget, the erossfhavingtle'parallel'bai-lich@ nearest 2o the eye of the operator, which will sight between tlie edges of the bars. As these bars are of a greater or less thickness and have their adjacent edgesor faces parallel with each other, a slit is thus formed between them, :5 through which the light from the'iield passes to the observer; and as unobstructed rays of light can only pass in straight lines, the target must be placed in the plane of this slit or the rays of light reected from it cannot pass 3o through the slit, as they will be obstructed by the opposite edges of the bars. By means of the arms i2 and 43 this slit between the crossbar and parallel bar above it can be increased from actual contact, when no light at all can 3 5 pass between them to the full swing of the arms. In taking very accurate observations, and especially by persons not used to such work, it is necessary to make the slit between the bars as narrow as possible, so that the center line of thetarget must 'be placed in a very limited plane or it cannot be seen. If it is placed too high the light from it will be intercepted by the edges of these bars, and if it is placed too low the light will be intercept-cd by the cross-bar at the opposite end of the level, the top edge of which is placed in the center of the plane of the slit. If such accurate sight is not required, the parallel bar may be raised, which will increase the limits of the field in 5o which the target can be seen and if the tarl get should be placed a triiie above the line of the ray of light which passes over the edge of the outer crossbar it can still be seen, as the ray of light from it can pass between the bars, although it passes above the top of the crossbar at the opposite end of the level; but if the target is placed too low it cannot be seen for the saine reason as when a finer sight'is being taken.

The cross-bars at the ends of the level-bar may be adjusted to have theirl upper edges perfectly level by means of the set-screws in the cross-heads, the said screws bearing against the lugs upon the lower edges of the crossbais, and thus support tlic cross-bars, which inay slide and rock upon the screws passing through their slots. V

'rations and formed with a circular upwardly j projecting flange and with a centralA The shank of the cross-head supporting t'lie- 1eve1-bar,being provided with the annular rini and reduced portion revolving, respectively, upon the annular riin of the frame and in the aperture of the rim, and having the axial Screw-bolt, will be pivoted perfectly true, so that after the frames have been adjusted per-l fectly horizontal the pivotal shank will be in a true vertical line, so that there will be no deviation when the level-bar is revolved ina horizontal plane.

The ball-andsocketjoint and the four screws in the four portions of the frame enable the said franie to be adjusted ina perfect horizontal plane, motion in all directions being possible by this joint and by the screws, which may be screwed up and down at opposite sides, adjusting the frames in their desired position.,

The upper frame, being secured within the flange of the-lower frame, will be held perfectly true, so that the beveled apertures in the centers of the frames will be held register ing perfectly true, preventing uneven wear and cutting of the spherical knob and consequent untrue adjustment of the instrument, and, if desired, the upper franie inay be forined with a ilaiige and have a portion` of the lower frame iitting into it, the saine results being attained. v 'i i Having thus described my invention, I claim and desire to secure by'Letters Patent of the v United St'atesj v' f i v r 1. In a surveyors level, the combination of a circular frame having a beveled^l central apcrturcand having thelevel-bar pivotcd above V v it, a frame having a circular flange upon its y. upper face fitting around the edge of the upper frame and having a central aperture' bev- 105 eled from above and having the upper traine secu red within the iiange, and aspherical knob projecting from the tripod and fitting within the bearing formed by the beveled apertures of the frames, as and for the purpose shown and set forth. 2 In a surveyors level, the combination of a frame supported upon a universal joint and having an upwardly-'facing aniinlar riin formed with a central perforationl having a narrower portion at its lower end, a shank projecting downward from the middle of the level-bar and having an annular downwardly-facing rim fitting upon the other riin and having a reduced portion fitting in the perforation of 12o the lower rim, and a screw'passing through the narrow portion of the perforation in thel r lower rim and passing np througliga central perforation in the shank having a nut at itsl upper end, as and for the purpose shown and set forth. -f "1' 3.1 In a surveyors level, the combination of j, 4- the tripod having a circular plate at its upper end formed with a central upwiardly-extending shank having a spherical knobat its up per end, a frame having lips projecting atrigl t angles and formed with screwfthreaded perfo IOO ilot

circula aperture beveledfroin above and fitting around Vthe spherical knob, a circular frame having a central aperture beveled from vbelow and fitting over the knoband having screws seeming.

' i5 ofthe perforation through an axial perforation inthe shank and having a nut at its upper end, as and for the purpose shown and set forth. A

4. In a surveyos level, the combination of 2o the levelbar having fiat faces at its ends and having grooves in the ends of its under side, cross-bars having slots at their middles for the passage of fastening-screws securingthem to the faces and having each a pair of downy 25 wardly-projeeting lugs at the middles of their lower edges, and flat bars secured inthe grooves of the under side of the bar and proi jecting withcrossshcads beyond theends of the level-bar and 'provided -with upwardlycxtendingzset-screws in their ends bearing with the upper ends against the downwardly-I projecting 'lugs of the flat hars, as and for the purpose shown and set forth. 5. In a surveyors level, the combination of a level-bar, a crossfbar lat each end, two arms secured to Aone of said cross-bars, and aparalici bar secured to the ends of said arms.

6. In a surveyors 1evel,'the combination of a level-bar, a cross-bar at-each end, two arms secured to one of said cross-bars, the 4end of 4o one of which armsis formed into a downwardly-projecting handle, and a parallel .barv secured to the opposite end of said arms.

In. testimony thatI claim the foregoing as my own I have hereunto affixed my signature 45 in presence of two witnesses. A .VILLIAM ABRAM WRIGHT.

e I'Vitnesses: l n l FRED W. MAXWELL, GEO'. BAnNE'rT. Y

Vss 

